I agree with the hardliners here.
I do not stand for rudeness or refusal to help.
However, general grumpiness is mostly ok as long as the teen is wiling to provide an explanation (eg, lots of work to do, argument with friend, feeling unwell, whatever) and, ideally, talk about it. Despite what my kids think, I do remember being a teen and it was hideous, so I don't blame them if they are less than happy at times.
But I think it's important to lead by example.
So, if I'm having a bad day - pmt, work stress, lack of sleep whatever - I tell them and apologise if I am grumpy and make sure they know it's not their fault. I don't expect them to do anything I wouldn't do myself, nor expect higher standards than I set for myself (I can't tell them never to swear, for example, because I swear sometimes (although never at them), so I teach them when it is or is not appropriate). And I pick my battles. So although I like a tidy house, I let it go if their rooms are untidy because in the grand scheme of things, what does it really matter? But I don't tolerate dirty crockery or food in their rooms because that encourages mice and means others don't have clean stuff to use.
I guess it's about setting an example and teaching consideration for others (and what goes around comes around...).